Beyond the common belief that eating carrots improves your eyesight, most of us don’t know much about the relationship between nutrition and our eyes. We tend to take them for granted, especially if our vision is good. But all of us—women in particular—would do well to pay more attention to the issue. According to the Women’s Eye Health Task Force at Boston’s Schepens Eye Research Institute, Americans’ vision problems are increasing at near-epidemic rates, and women comprise two-thirds of those affected.
Eye disease is on the rise for many reasons, among them greater longevity. “Vision itself also declines because of how we use our eyes—constant ‘near work’ in schools and on computers,” says Marc Grossman, OD, LAc, author of Greater Vision (McGraw-Hill, 2001). Older women are more likely to suffer from a cataract (clouding of the eye’s lens). And for a variety of reasons, they are also more likely to develop ocular symptoms associated with rheumatological diseases such as lupus, and macular degeneration, in which the retina’s macula—the source of clear, sharp vision—gradually breaks down. Prevent Blindness America cites 1 in 3 people over 65 as at risk for this major cause of blindness, with women twice as likely to develop it. In addition, as women age, hormonal changes can contribute to dry-eye syndrome, in which decreased tear production fails to lubricate the eye’s surface adequately.
Nutrition plays an active role in eye health. In fact, recent research shows that more than a quarter of the nutrients absorbed from food go toward nourishing our sight. “Diets of processed foods and sugar don’t nourish the eyes,” Grossman says, and because eyes are directly exposed to air and ultraviolet rays, they are more vulnerable to free radical damage. “The resulting oxidative stress reduces the level of naturally occurring antioxidants in the eyes over time, which is the major factor behind most eye disease.”
To keep your eye health as sharp as possible, keep the following vision-care tips in view.
Get your A to Zinc
The antioxidants found in many vitamins and minerals can both prevent and reduce the free radical damage and oxidation that lead to macular degeneration and cataracts. Patients with advanced macular degeneration who took antioxidants twice daily experienced a 25-percent reduction in the disease’s progression and maintained significantly better sight in their stronger eye, according to a study by the National Eye Institute (Journal of the American Optometric Association, 1996, vol. 67, no. 1).
Among the most effective antioxidants for eyes is vitamin A, which aids night vision, color vision, and the ability to adapt to changes in light. Good vegetable sources of beta-carotene, which is converted into vitamin A in the body, include winter squashes and orange root vegetables such as carrots and yams. Zinc, found in poultry, wheat, and mushrooms, assists vitamin A absorption and helps prevent night blindness and macular degeneration. Riboflavin (vitamin B2), found in beans and whole grains, regenerates antioxidants after they’ve neutralized free radicals and prevents eye burning and itching, loss of visual acuity, and light sensitivity. Grossman recommends striving for a daily intake of 15,000 to 25,000 IUs of beta-carotene (three to five times the RDA), 30 mg of zinc, and 10 mg of riboflavin, augmenting your diet with supplements as necessary.
Vitamin C—which is more concentrated in healthy eyes and adrenal glands than almost anywhere in the body—provides a natural filter against UV rays, Grossman says. It also helps synthesize glutathione, an eye antioxidant produced by the body, whose diminished levels may lead to cataracts, macular degeneration, and glaucoma. In addition to eating citrus fruits, peppers, tomatoes, and cruciferous vegetables rich in vitamin C, Grossman recommends supplementation of at least 500 mg a day. Vitamin E—together with vitamin C, alpha-lipoic acid, and cysteine (an amino acid found in eggs, as is vitamin E)—also protects against lens damage from UV rays, decreasing cataract risk by up to 45 percent. Selenium, found in Brazil nuts, garlic, and seafood, aids vitamin E absorption and helps the body produce its own antioxidants.
Opt for omega-3s
Omega-3 fatty acids in cold-water fish, flaxseed oil, hempseed, and walnuts have been shown to protect against macular degeneration. Because of the high mercury levels found in some fish, Grossman instead recommends taking 1 to 2 teaspoons of high-quality fish oil per day.
Eat your greens, yellows, and oranges
Carotenoids—including alpha- and beta-carotene along with xanthophylls, lutein, and zeaxanthin—add yellow, orange, and red color to food. They may also be our vision’s best assets. Studies increasingly reveal the power of lutein (found in dark green leafy vegetables such as spinach, kale, and collard greens) and zeaxanthin (found in corn, peaches, mangoes, and other yellow produce) to guard against macular degeneration and even reverse some of its effects. Both increase the retina’s macular-pigment density, which protects it from degenerating or tearing. Harvard researchers found that eating 6 mg of lutein a day (roughly 1/4 cup cooked spinach) lowered the odds of macular degeneration by 43 percent (Journal of the American Medical Association, 1994, vol. 272, no. 18). Another lutein study showed improvement in visual function in one or both eyes of subjects with macular degeneration. And because lutein filters out UV rays, cataract risk also dropped by up to 65 percent in those who ate spinach and other greens five or more times per week, according to another study.
Cooked tomatoes are a good food source because cooking releases lutein from tomatoes’ cell walls, says Grossman. When taken as individual supplements, vitamin A and lutein compete for absorption, so they should be consumed separately. For the same reason, Grossman recommends taking lutein and zeaxanthin separately from beta-carotene.
Skip unhealthy fats and sugar
Traditional Chinese Medicine views the liver as the primary meridian responsible for eye health, according to New Paltz, New York acupuncturist Michael Edson, MS, LAc. A healthy liver supports vision by contributing to the free flow of energy and blood throughout the body and by converting beta-carotene into vitamin A.
Avoiding fried foods and partially hydrogenated fats (which place undue stress on the liver) can help improve night vision, adaptation to bright light, and adequate tear production, he says. Cut down on sweets, too, says Grossman, because sugar has been shown to impair the lens’ ability to keep itself clear. (He does note that adequate amounts of vitamin C can prevent and even reverse this negative effect.) And stay hydrated. Drink the recommended eight to ten glasses of water a day, and avoid carbonated, caffeinated, and alcoholic beverages that dehydrate eye tissue and lead to reduced tear production and dry, uncomfortable eyes.
Bilberry, a European version of blueberries, is called the “vision herb” because it improves night vision and can prevent glaucoma, cataracts, and computer-vision fatigue. Its antioxidant flavonoid compounds also strengthen retinal capillaries and can prevent or treat early-stage macular degeneration. Recommended doses for prevention and treatment range from 120 mg to 300 mg per day in capsules or tablets. Clinical trials also have shown that 120 mg to 240 mg of ginkgo biloba can be used to treat early-stage macular degeneration.
For complete nutritional protection for eyes, Grossman recommends a liquid supplement that, when taken sublingually, provides recommended doses of bilberry and ginkgo together with retina-strengthening lutein and zeaxanthin.
You can take simple steps every day to protect your eyes. To guard against retina-damaging UV rays, choose wraparound, UV-blocking sunglasses, along with a broad-brimmed hat or visor. Avoid cigarette smoke: Smoking increases the risk of macular degeneration 2.4-fold in women, depletes antioxidants like vitamin A, and causes about 20 percent of all cataracts, increasing female smokers’ risk by 63 percent. If you use eyedrops, choose tear substitutes without preservatives, or vitamin A-based drops that provide antioxidant protection. Preservatives in most commercial eyedrops actually decrease production of tears or even damage corneal cells, Grossman notes.
Regular exercise—at least 20 minutes daily—improves circulation throughout the body, including the eyes with their many small vessels, and helps eliminate toxins, Grossman says.
Researchers found that glaucoma patients who took brisk, 40-minute walks five days a week for three months reduced their intraocular pressure by approximately 2.5 millimeters, similar to the reduction seen with beta-blockers. Beta-blockers, often used in glaucoma eyedrop treatments because of their ability to lower intraocular pressure, can also cause undesirable side effects such as fatigue, elevated blood sugar levels, and weight gain. Exercise offsets all of these potential side effects. To get a comprehensive picture of your eye health, be sure to visit your optometrist or ophthalmologist at least every two years, and annually if you’re over 50. In the meantime, remember that eating a healthy diet, supplementing wisely, and protecting your eyes from daily environmental damage can help you see more clearly for years to come.
Phyllis Edgerly Ring wrote “Dread Your Annual?” for the October 2003 issue.